The present invention relates to purification of human prostatic acid phosphatase including separation of the different isoenzymes of the phosphatase from each other. The phosphatase in question is of particular significance in connection with the diagnosis of prostatic diseases.
Estimation of acid phosphatase activity (orthophosphoric-monoester phosphohydrolase) in serum has served in the diagnosis of the prostatic carcinoma since the report by Gutman et al. in J.Clin. Invest., vol 17, p. 473 (1938). An increased total acid phosphatase activity in serum, has been observed in sera of patients with prostatic cancer. However, observations concerning the activities in sera, prostatic secretions, and tissue itself in relation to age, physiological atrophy, and pathological conditions have been inconsistent and largely contradictory. One reason for this may be the actual variations of enzyme activity, but it also seems that the prostatic enzyme is not specifically detected by the methods presently available.
It is apparent that satisfactory results in the diagnosis of prostatic diseases could be obtained by use of immunobiochemical applications. For this purpose it would be necessary to isolate an isoenzyme of the phosphatase in a highly pure condition. There have been purification procedures for prostatic acid phosphatase described in the prior art, these procedures comprising various precipitations and chromatographic steps. However, the results have not been completely satisfying with respect to the specific activity and recovery of the enzyme.